The impact of posttraumatic stress disorder on impairment in the UK military at the time of the Iraq war

Abstract

The aims of this study were to assess: (1) the relationship between PTSD and impairment, (2) whether there is a threshold in the association of PTSD score and impairment, and (3) whether any of the PTSD criteria are more strongly associated with impairment. We studied 10,069 service personnel from a representative sample of the British Armed Forces to assess the effects of the Iraq war. Participants completed the PTSD checklist (PCL), the general health questionnaire-12 (GHQ-12), the alcohol use disorder identification test (AUDIT) and five questions to assess impairment. 78% of those with a PCL-score of 50 or more endorsed at least one impairment item in comparison to 27% of those with a score below 50. The odds ratio (OR) of impairment in the PCL group with a score of 50 or more was 16.7 (95% CI 12.9–21.6). There was an increasing risk of impairment with an increasing category of PCL-score without a noticeable threshold. For each PTSD subscale: intrusiveness, avoidance/numbing and hyper-arousal, divided into four score categories, there was an increased association with impairment, but the association of avoidance/numbing with impairment was the greatest and independent of the other two criteria (OR 7.2 (95% CI 4.8–10.9). Having a good relationship with a partner had minimal effect on the level of association between PTSD and impairment. Functional impairment is a serious problem for those with PTSD. The impairment is not confined to those with the highest PCL-score. Avoidance/numbing is the criterion which makes the greatest independent contribution to impairment

Introduction

Functional impairment is a common feature of posttraumatic stress disorder (PTSD) in civilians (Amaya-Jackson et al., 1999, Breslau et al., 2004, Marshall et al., 2001, Stein et al., 1997) and military personnel (Caspi et al., 2007, Dohrenwend et al., 2006, Grubaugh et al., 2005, Schnurr et al., 2000). However, among military studies there is variation in the prevalence and level of severity of impairment in those with PTSD (Dohrenwend et al., 2006, Frueh, 2007). Impairment is not only a characteristic of PTSD patients, but also of those who do not entirely fulfill the diagnostic criteria, usually called partial PTSD (Breslau et al., 2004, Grubaugh et al., 2005, Marshall et al., 2001, Schnurr et al., 2000, Stein et al., 1997, Weiss et al., 1992;). Some commentators have emphasized that co-morbidities, including depression, may be partly responsible for this association (Momartin et al., 2004, North et al., 1999).

Most reports concerning PTSD and impairment in the military have been restricted to Vietnam veterans (Frueh, 2007) or to specific ethnic groups (Caspi et al., 2007). It has been reported that impairment is common among Vietnam veterans with current PTSD (Dohrenwend et al., 2006), but some have argued that the measurement scale used in that study was skewed towards identifying impairment (Frueh, 2007). This view is supported by the high percentage of those with PTSD whose level of impairment consisted of “some difficulty in social, occupational or school functioning but generally functioning pretty well”. Others have argued that this level of impairment is the appropriate threshold in veterans experiencing PTSD 11–12 years after the event (Kilpatrick, 2007).

The short forms of the quality of life questionnaire (the SF-12 or SF-36) (Ware et al., 1993) have been used in the military to assess quality of life (Boehmer et al., 2003, McKenzie et al., 2004, Proctor et al., 2001, Voelker et al., 2002), but rarely for inferring what impact PTSD has on personnel’s social and work functioning (Grubaugh et al., 2005, Schnurr et al., 2000). Whilst there is an implicit acceptance that those with PTSD will endure some degree of impairment, some studies have shown that numbing and avoidance may be more important in their contribution to the level of impairment than other PTSD criteria (Foa et al., 1995, Norman et al., 2007, North et al., 1999). It has been reported that endorsement of questions on numbing and avoidance is among the lowest prevalence in subjects who experienced a recent trauma (North et al., 1999, Schutzwohl and Maercker, 1999). We do not know whether these findings are relevant to a military population.

We report the results of a study carried out between 2004 and 2006 to assess the effect of the Iraq war on psychological symptoms (Hotopf et al., 2006). As well as assessing PTSD symptoms we used some items of the SF-36 to assess quality of life in relation to occupational and social functional limitations. We also assessed respondents’ satisfaction with long term relationships. The aim of this study is to assess the relationship between PTSD and functional impairment and whether there was a threshold in the association of PTSD score and impairment. We also examined whether any of the component criteria of the PTSD construct, intrusiveness, numbing/avoidance and hyper-arousal, were more strongly associated with impairment than other criteria, and the influence of co-morbidity and relationship satisfaction with a partner on any possible associations.